Previous attempts to incorporate biocidal activity into materials and coatings have primarily involved two methods—physical mixing (blending) of biocides into the materials and coatings, and chemical binding of biocidal functional groups to the polymers or copolymers comprising the materials and coatings. Chemical binding should be preferable for long-term biocidal activity if the bound biocidal functionality does not adversely affect the other desired properties such as strength, appearance, and chemical resistance of the material or coating. For example, a significant amount of work has been performed concerning rendering sponges biocidally active. This involves encapsulation of a variety of weak biocides into the porous structure of the sponge, either through physical blending or chemical bonding to the surface. The sponges modified in this manner can exhibit biocidal activity, but the contact times necessary for action are generally long, and some pathogens are not inactivated even at contact times of several hours. Anti-fouling polyurethanes have been prepared by chemical incorporation of tributyl tin as described in U.S. Pat. No. 5,194,504, and quaternary ammonium salts (see for example, J. Appl. Polym. Sci. 50: 663 (1993); J. Appl. Polym. Sci. 50: 671 (1993)). Coatings containing organo tin compounds are being discredited as threats to the environment, and poly-quats are weak biocides which are nonregenerable.
Poly-1,3-dichloro-5-methyl-5-(4′-vinylphenyl)hydantoin is a non-toxic, non-irritating, polymer that has been described in U.S. Pat. No. 5,490,983, which has been shown to exhibit biocidal properties (see Ind. Eng. Chem. Res. 33:168 (1994); Water Res. Bull. 32:793 (1996); Ind. Eng. Chem. Res. 34:4106 (1995); J. Virolog. Meth. 66:263 (1997); Trends in Polym. Sci. 4:364 (1996); Water Cond. & Pur. 39:96 (1997)). This polymer is effective against a broad spectrum of pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Klebsiella terrigena, poliovirus, and rotavirus, among others, causing large log reductions in contact times of the order of a few seconds in water disinfection applications.
Compounds with N-Halamine functional groups such as hydantoins, oxazolidinones, and imidazolidinones have also been employed recently in producing biocidal cellulose (U.S. Pat. No. 5,882,357), biocidal films on surfaces (U.S. Pat. Nos. 5,902,818 and 6,969,769), biocidal Nylon (Lin et al., J. Appl. Polym. Sci., 81, 943 (2001)), and biocidal polyester (Lin et al., J. Appl. Polym. Sci., 85, 177 (2002)). The U.S. Pat. Nos. 5,882,357 5,902,818 and 6,969,769 and the Articles Lin et al., J. Appl. Polym. Sci., 81, 943 (2001) and Lin et al., J. Appl. Polym. Sci., 85, 177 (2002) are all hereby incorporated by reference. However, these N-Halamine-based biocides have limited applications for coating materials.
Because of the aforementioned environmental hazards of tin-based biocidal materials and the limited application of the previously known N-Halamine biocidal materials, there is a continued need for more effective biocidal coatings and materials.